unknown helmet

[abbl]

Does somebody have an idea what this helmet is?
Don't know nationality or purpose.
Was found in Belgium.

The sheet metal is half mm thick and everything is rivetted.
There are 4 smal holes on the edge 2 in front and 2 in the back.







[/IMG]http://i209.photobucket.com/albums/bb224/steur/foto12.jpg[/IMG]

[Gran Sasso]

Remains of a german Luftwaffe protection helmet SSK90

[abbl]

thank you for the help

[bolo]

Ssk 90